1. Field of the Invention
The present invention relates to a method and apparatus for associating a station (STA) with an Access Point (AP) and, more particularly, to an authentication procedure between an STA and an AP.
2. Related Art
A recent Wireless LAN (WLAN) technology is basically evolving in three directions. There are Institute of Electrical and Electronic Engineers (IEEE) 802.11ac and IEEE 802.11ad as efforts to further increase the transfer rate on the extension line of an existing WLAN evolution direction. IEEE 802.11ad is a WLAN technology using a 60 GHz band. Furthermore, a wide area WLAN that utilizes a frequency band of less than 1 GHz in order to enable wider area transfer than that of the existing WLAN in distance is recently emerging. The wide-area WLAN includes IEEE 802.11af using a TV White Space (TVWS) band and IEEE 802.11ah using a 900 MHz band. A main object of the wide-area WLAN is to extend extended range Wi-Fi service as well as a smart grid and a wide area sensor network. Furthermore, an existing WLAN Medium Access Control (MAC) technology is problematic in that an initial link setup time is very long according to circumstances. In order to solve such a problem and in order for an STA to rapidly access an AP, IEEE 802.11ai standardization activities are recently carried out actively.
IEEE 802.11ai is a MAC technology for handling a fast authentication procedure in order to significantly reduce the initial setup and association time of a WLAN, and standardization activities for IEEE 802.11 ai have been started as a formal task group on January, 2011. In order to enable a fast access procedure, in IEEE 802.11ai, a discussion on the simplification of the procedure in fields, such as AP discovery, network discovery, Time Synchronization Function (TSF) synchronization, authentication & association, and a procedure convergence with a higher layer, is in progress. From among them, ideas, such as procedure convergence using the piggyback of a Dynamic Host Configuration Protocol (DHCP), the optimization of a full Extensible Authentication Protocol (EAP) using a concurrent IP, and efficient and selective Access Point (AP) scanning, are being actively discussed.